you can try to set a charset option on the configuration. see DEFAULT_CHARSET here: https://github.com/vert-x3/vertx-mysql-postgresql-client/blob/12a6e6f894/vertx-mysql-postgresql-client-jasync/src/main/java/io/vertx/ext/asyncsql/impl/MYSQLClientImpl.java

Although I haven't tested it myself.

That does not work well, actually. From here you can see it always using the default charset mapping and from here you can find only 83, 65, 69 valid. Other values seem not supported.

Yes, I see.
I couldn't find the value for the utf8mb4 in mysql docs. what I did find is that this is the default since 8.0.1.

If you have an idea of that value we can try that out.

I think the “SHOW COLLATION” statement should give you the id. An example: https://dev.mysql.com/doc/refman/8.0/en/charset-mysql.html

from reading this post. it looks like older utf in mysql was not totally compatible.
What I think to do is to change utf8 type in the protocol like this: CharsetUtil.UTF_8 to 224.

I tested it and it works. it might affect legacy databases that do not support this charset.

I will open an issue in jasync-sql itself for this.

@swordfeng - you're welcome to test it with jasync 0.9.50.

@oshai Tested and it looks good! I think I can close the issue now. Thanks!